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Bahan Standar Internal dengan Matriks Stream Sediments dari Sungai Berair Payau dan Tawar di Daerah Pangandaran dan Sekitarnya Irzon, Ronaldo; Kurnia, Kurnia
Jurnal Geologi dan Sumberdaya Mineral Vol 16, No 2 (2015): Jurnal Geologi dan Sumberdaya Mineral
Publisher : Pusat Survei Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (535.954 KB)

Bahan standar merupakan persyaratan mutlak untuk memvalidasi sebuah pengukuran. Dibutuhkan biaya besar dalam pengajuan bahan standar berskala certified reference material, oleh karena itu pembuatan materi acuan standar intern dapat menjadi jalan keluar. Sebagai sarana pengujian di lingkungan Pusat Survei Geologi, Laboratorium Geologi harus dapat menyelaraskan fungsinya dengan kebutuhan riset ilmu kebumian di Indonesia. Beberapa tahun sebelumnya tiga bahan standar dengan matriks stream sediment telah dihasilkan. Walaupun sama-sama dari matriks stream sediment, penelitian ini berbeda pada jenis air dimana contoh diambil. Dua dari contoh diambil dari lingkungan air payau, sedangkan satu lainnya dari lingkungan air tawar di sekitar Pangandaran, Jawa Barat. Perangkat Atomic Absorbance Spectrometry dan X-Ray Flourescence dimanfaatkan untuk mengukur kandungan elemen maupun oksida pada contoh bakal standar yang telah melalui proses hingga menjadi banyak split. Perhitungan statistika diaplikasikan untuk mengetahui tingkat homogenitas contoh maupun menetapkan nilai acuan. Uji variansi satu arah berakurasi 95% menyimpulkan bahwa dua contoh dapat dikategorikan homogen dan satu lainnya homogen sempurna. Atas dasar besaran koefisien variansi <5%, lima elemen hasil analisis AAS dan delapan oksida utama hasil analisis XRF dapat dijadikan nilai acuan.Kata kunci - air payau, air tawar, bahan standar internal, stream sediment.

PERBANDINGAN CALORIFIC VALUE BERAGAM BAHAN BAKAR MINYAK YANG DIPASARKAN DI INDONESIA MENGGUNAKAN BOMB CALORIMETER Irzon, Ronaldo
Jurnal Geologi dan Sumberdaya Mineral Vol 22, No 4 (2012): Jurnal Sumber Daya Geologi
Publisher : Pusat Survei Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (213.714 KB)

Calorific value is amount of released energy when a known volume of gas is completely combusted. Now, the market of fuels in Indonesia is not only owned by Pertamina, but there have been many gas stations conducted by foreign companies since 2005. One of the most famous ways to rank the fuels' performance is based on research octane number (RON). A different kind of fuels' calorific value with various octane number sold in many gas stations would be important information for fuel customers. The use of the bomb calorimeter to analyze the calorific value has been published in diverse applications. Although bomb calorimeter is viable to measure the heat content of the liquid, we can not easily find a writing of using the equipment on this kind of sample. The method used here has been successful to measure the calorific values of three liquid samples using bomb calorimeter. This study quantifies calorific value of eight gasoline and five diesel samples of 83 measurements. Statistics measurements of at least six times repetition indicate: the method have very good stability (%RSD = 0.09 – 0.63%), there are differences in colorific value on samples with same octane number produced by different company, increase in octane number also raises the samples' calorific value, and the ratio of fuel's price to their heat content is still lame.Keywords : bomb calorimeter, calorific value, fuel, octane number

Element Mobilization During Weathering Process of Ultramafic Complex in North Konawe Regency, Southeast Sulawesi Based on A Profile from Asera Irzon, Ronaldo; Abdullah, Baharuddin
Indonesian Journal on Geoscience Vol 5, No 3 (2018)
Publisher : Geological Agency

DOI: 10.17014/ijog.5.3.277-290The North Konawe Regency, located in the northern part of the southeast arm of Sulawesi Province, is occupied mainly by Ophiolite Complex. Recent studies on weathering of ultramafic complex have been focussed on the composition of laterite in relation to heavy metal explorations. In Asera area, North Konawe, a 3.1 m wide outcrop of ultramafic rocks is related to nickel laterite potential. In this study, an elemental change during the weathering process is discussed, including the mobilization of rare earth elements. XRF and ICP-MS from The Centre for Geological Survey of Indonesia are the two important geochemistry instruments used in this study. Si, Mg, and Ca are depleted during weathering, whilst the enriched elements are Fe, Al, Ti, and some heavy metals such as Cr, Mn, and Co. A different mobilization pattern is detected on Ni, because of its relation to Mg. Cs, Rb, and Ba are concentrated in a clayey horizon of upper laterite. The increase of REE concentrations is parallel to both Fe and Mn which rises to the top of laterite. Ce and Eu negative anomaly trends indicate oxidizing condition through the weathering process, although the studied profile, influenced by allochthon material, morphology condition, and geochemistry composition, indicates that the transported rock fragments were originated from ultramafic rock.

Petrology and Geochemistry of The Volcanic Arc Tarusan Pluton in Comparison to Lolo Pluton, West Sumatra Irzon, Ronaldo; Syafri, Ildrem; Agustiany, Irfani; Prabowo, Arief; Sendjaja, Purnama
Jurnal Geologi dan Sumberdaya Mineral Vol 20, No 4 (2019): Jurnal Geologi dan Sumberdaya Mineral
Publisher : Pusat Survei Geologi

The Volcanic Arc Suite is the group of batholiths in the range of the Barisan Mountains and mostly denotes I-type affinity. Previous investigations of the intrusions in West Sumatra emphasized the crystallization age without completing geochemistry characteristics. No former study discussed a pluton which mapped in the Kota XI Tarusan District. This study explains the geochemistry and petrology of the Tarusan Pluton using polarized microscope, XRF, and ICP-MS at the Center for Geology Survey of Indonesia. The microscopic analysis confirms the granite character of the samples. Although both plutons are identified as I-type calc-alkaline series, the Tarusan Pluton is peraluminous granite whilst the Lolo Pluton denotes wider range from metaluminous to peraluminous of granodiorite to granite. Both the plutons are clearly classified as volcanic arc granitoid in the correlation to Volcanic Arc Suite of Sumatra. Negative Ba, Nb, and P anomalies together with positive K, Nd, and Y anomalies are pronounced on the two felsic intrusions. Negative Eu anomaly on the Tarusan Pluton but the positive one at the Lolo Pluton might explain different magma evolution process.Keywords: volcanic arc granite, geochemistry, Tarusan Pluton, Lolo Pluton.

Plagioclase Fractionation On The Holocene Volcanic Rocks Evolution In West Halmahera Regency Ipranta, Ipranta; Irzon, Ronaldo
Jurnal Geologi dan Sumberdaya Mineral Vol 20, No 3 (2019): Jurnal Geologi dan Sumberdaya Mineral
Publisher : Pusat Survei Geologi

The tectonic complexity in the Maluku region is caused by the interaction of the three main platesin this area, namely: the Philippine Plate, the Australian Plate, and the Eurasian Plate. The origin of volcanic rock-forming material from Jailolo Mount., Sahu Mount., Gamkonora Mount., and Ibu Mount. in West Halmahera Regency is the aim of this study. Petrographic, trace elements, rare earth elements analysis are also used to study rock formation processes and correlations between sample groups. Bipolar microscope and Inductively Coupled Plasma - Mass Spectrometry of the Center for Geological Survey Laboratory are the analytical devices used in this study. Almost all samples are classified as andesite based on the comparison of the quartz, K-feldspar, and plagioclase compositions. There is a possibility of mixing between oceanic crust and continental crust of the studied Holocene volcanic which is indicated by La/Yb versus Nb/La diagrams. Fractional crystallization is considered more influential in rock formation compared to partial melting. The effect of plagioclase fractionation on the four volcanic rock groups is shown by the Y versus Sr/Y diagram and rare earth spider diagram patterns. Increased levels of rare earths in samples from G. Gamkonora and G. Sahu are strongly influenced by crystallization of plagioclase during rock formation.Key words: volcanic rocks, petrography, geochemistry, West Halmahera

SKEMA FIRE ASSAY DAN ICP-MS PADA PENGUKURAN KADAR PALADIUM DALAM SAMPEL BATUAN Irzon, Ronaldo; Kurnia, Kurnia
Majalah Ilmiah Pengkajian Industri Vol 13, No 2 (2019): Majalah Ilmiah Pengkajian Industri
Publisher : BPPT

Paladium adalah anggota Platinum Grup Element yang berjumlah kecil di kerak Bumi, namun memiliki harga jual yang tinggi. Logam ini sangat dibutuhkan oleh industri otomotif, industri pesawat ruang angkasa, dan industri perhiasan. Akurasi pengukuran Pd yang baik pada sampel diperlukan untuk mendukung industri terkait. Penelitian ini bertujuan untuk menjabarkan akurasi pengukuran paladium yang memanfaatkan skema fire assay dalam pra-konsentrasi dan ICP-MS sebagai perangkat pengukuran. Sampel yang dipergunakan adalah bahan internal standar Serpentin milik Laboratorium Geologi. Limit deteksi cukup rendah pada 1,0057 ppb yang ditentukan melalui skema regresi linear. Stabilitas kinerja perangkat sangat baik yang ditunjukkan oleh rentang deviasi 0-1,96%. Prosedur fire assaying yang belum sempurna disimpulkan menjadi penyebab perbedaan hasil pengukuran kadar Pd pada sampel. Rangkaian proses dalam studi ini dinilai akurat yang mengacu pada besaran spike recovery <112%. Studi ini dapat dikembangkan dengan memperbesar rentang kalibrasi analisis agar dapat mengakomodasi kisaran jumlah analit yang lebih luas pada sampel

SKEMA FIRE ASSAY DAN ICP-MS PADA PENGUKURAN KADAR PALADIUM DALAM SAMPEL BATUAN Irzon, Ronaldo; Kurnia, Kurnia
Majalah Ilmiah Pengkajian Industri Vol 13, No 2 (2019): Majalah Ilmiah Pengkajian Industri
Publisher : BPPT

Paladium adalah anggota Platinum Grup Element yang berjumlah kecil di kerak Bumi, namun memiliki harga jual yang tinggi. Logam ini sangat dibutuhkan oleh industri otomotif, industri pesawat ruang angkasa, dan industri perhiasan. Akurasi pengukuran Pd yang baik pada sampel diperlukan untuk mendukung industri terkait. Penelitian ini bertujuan untuk menjabarkan akurasi pengukuran paladium yang memanfaatkan skema fire assay dalam pra-konsentrasi dan ICP-MS sebagai perangkat pengukuran. Sampel yang dipergunakan adalah bahan internal standar Serpentin milik Laboratorium Geologi. Limit deteksi cukup rendah pada 1,0057 ppb yang ditentukan melalui skema regresi linear. Stabilitas kinerja perangkat sangat baik yang ditunjukkan oleh rentang deviasi 0-1,96%. Prosedur fire assaying yang belum sempurna disimpulkan menjadi penyebab perbedaan hasil pengukuran kadar Pd pada sampel. Rangkaian proses dalam studi ini dinilai akurat yang mengacu pada besaran spike recovery 112%. Studi ini dapat dikembangkan dengan memperbesar rentang kalibrasi analisis agar dapat mengakomodasi kisaran jumlah analit yang lebih luas pada sampel

Contrasting Two Facies of Muncung Granite in Lingga Regency Using Major, Trace, and Rare Earth Element Geochemistry Irzon, Ronaldo
Indonesian Journal on Geoscience Vol 2, No 1 (2015)
Publisher : Geological Agency

DOI:10.17014/ijog.2.1.23-33Lingga Regency is located in the main range of the famous Southeast Asia granitic belt related to tin resources. There are two granitic units in this region: the S-type Muncung Granite and I-type Tanjungbuku Granite. XRF and ICP-MS were used to measure the major, trace, and rare earth elements of nine Muncung Granite samples. Two different patterns were identified from major data plotting on Harker variation diagram. Granitic rocks from Lingga and Selayar Islands are classified as A facies while others from Singkep Island is B facies. This paper used graphs and variation diagrams to reveal the differences of those two facies. Thus, REE correlation to SiO2, trace element spider diagram, and REE spider diagram show more contrasts correlation. However, both facies are syn-collisional and High-K calc-alkaline granites. Some identical characters with other granitic units in Peninsular Malaysia were also detected in this work.

Contrasting Two Facies of Muncung Granite in Lingga Regency Using Major, Trace, and Rare Earth Element Geochemistry Irzon, Ronaldo
Indonesian Journal on Geoscience Vol 2, No 1 (2015)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.2.1.23-33

DOI:10.17014/ijog.2.1.23-33Lingga Regency is located in the main range of the famous Southeast Asia granitic belt related to tin resources. There are two granitic units in this region: the S-type Muncung Granite and I-type Tanjungbuku Granite. XRF and ICP-MS were used to measure the major, trace, and rare earth elements of nine Muncung Granite samples. Two different patterns were identified from major data plotting on Harker variation diagram. Granitic rocks from Lingga and Selayar Islands are classified as A facies while others from Singkep Island is B facies. This paper used graphs and variation diagrams to reveal the differences of those two facies. Thus, REE correlation to SiO2, trace element spider diagram, and REE spider diagram show more contrasts correlation. However, both facies are syn-collisional and High-K calc-alkaline granites. Some identical characters with other granitic units in Peninsular Malaysia were also detected in this work.

KAOLINITISASI DAN MOBILITAS UNSUR TANAH JARANG PADA PROFIL PELAPUKAN BATUAN GUNUNGAPI DI PUNCAK MANDEH, SUMATRA BARAT: KAOLINITIZATION AND RARE EARTH ELEMENTS MOBILIZATION OF A VOLCANIC ROCK WEATHERING PROFILE IN PUNCAK MANDEH, WEST SUMATRA Irzon, Ronaldo; Kurnia; Sendjaja, Purnama; E. Setiawan, Verry
Buletin Sumber Daya Geologi Vol. 16 No. 1 (2021): Buletin Sumber Daya Geologi
Publisher : Pusat Sumber Daya Mineral Batubara dan Panas Bumi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.47599/bsdg.v16i1.312

The weathering process occurs on the Earth's surface, especially in tropical climates, and causes the parent rock's mobilization of elements. Weathering is interesting because it is often associated with the enrichment of economic materials such as iron, alumina, and REEs. The weathering profile of Tertiary volcanic rocks is spread across tropical Sumatra. This study aims to describe REEs' kaolinization and mobilization process on the weathering profile of volcanic rocks in the east of Mandeh Peak, West Sumatra. XRF and ICP-MS devices are utilized to measure the abundance of major oxides, trace elements, and REEs. The increase in IOL is proven to occur in the same direction as weathering levels. A triangular diagram of SiO2-Al2O3-Fe2O3T indicates kaolinization on weathering at Mandeh Peak. Feldspar and mica were prone to weathering and instantly turn into kaolinite in the early stages of weathering to explain the main oxide variations in weathering profiles. The weathering process has increased the amount of alumina and iron significantly relative to the parent rock. There is no REEs enrichment on any of the weathering horizons other than its composition on the parent rocks. Part of Ce is oxidized into Ce4+ and left on the saprolite horizon. This condition makes Ce's mobility in the direction of weathering level is different from other REEs.

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